Arrange the following in the decreasing negative electron gain enthalpy :
`B,C,N,O`

Answer

N>B>C>O

Explanation

N has + ve electron gain enthalpy while all others have- ve electron gain enthalpies. Since size decrease in moving from B `to C to O` therefore electron gain enthalpies become more and more negative from B `to C to O`. Thus the overall decreasing order of electron gain enthalpies is N ,B ,C, O